Introduction: Osteomas are benign tumors, with slow growth and a long period of asymptomatic development. The paranasal sinuses are often involved, the most affected one being the frontal sinus, followed by the ethmoid, maxillary and sphenoid sinuses. Etiologically, theories of inflammatory, traumatic, genetic genesis should be introduced, but the issue still remains unclear. The diagnosis is very often accidental, when performing radiography or computed tomography (CT). Clinically manifested osteomas with headache, facial deformity, mucocele, intracranial complications are subject to timely surgical intervention. The choice of surgical approach depends on the size of the osteoma and the location, as well as on the professional and technical capabilities given the more specific requirements for the instrument. Materials and methods: We present a clinical case of a 28-year-old man with complaints of headache in the frontal facial area. An X-ray revealed an osteoma in the area of the left frontal sinus, involving more than 2/3 of its cavity. CT was performed and a discussion of the possibilities of endoscopic endonasal surgery, given the borderline „giant“ osteoma with a diagonal size of about 2.75 cm (> 3 cm). An endoscopic endonasal approach was applied. Results: Endoscopic endonasal surgery was performed. The chosen surgical approach was Draf 3 type frontotomy with osteoma extirpation. In early postoperative period– 5 days, there aren’t registreted complications. The patient was followed endoscopically in the second week, first month, sixth month. A month later, a control CT scan was performed with data on residuality on the anterior wall of the frontal sinus, without drainage disturbance. Clinically, the patient has no complaints. There are no late postoperative complications. Conclusion: Symptomatic osteomas of the paranasal sinuses require timely surgery. The choice of surgical approach (open with osteoplastic flap, endonasal or combined) depends on the anatomical location, the size of the tumor, as well as the experience of the surgeon and the technical capabilities of the hospital. Endoscopic endonasal surgery is popular, with highly valued capabilities over time, but in „giant“ osteomas it is debatable given the risk of residuality.